What is the recommended technique for a digital rectal examination (DRE) of the prostate gland?

Recommended Technique for Digital Rectal Examination (DRE) of the Prostate

The optimal technique for digital rectal examination (DRE) of the prostate involves having the patient in the left lateral decubitus position with knees flexed toward the chest, using a well-lubricated gloved index finger to systematically examine the entire accessible portion of the prostate gland, focusing on symmetry, consistency, and presence of nodules or induration. 1

Patient Positioning and Preparation

• Left lateral decubitus position is preferred as it provides better access to the prostate compared to the supine position
• Have the patient flex his knees toward his chest to improve access to the prostate, especially in overweight or obese patients 2
• Research shows that in the supine position, 42% of prostates are non-palpable, compared to only 8% in the lateral decubitus position 2
• Patient should be informed about the procedure and asked to relax to minimize discomfort

Examination Technique

1. Preparation:

   • Wear examination gloves
   • Apply adequate lubricant to the index finger
   • Inform the patient before beginning the examination

2. Insertion:

   • Gently insert the lubricated index finger into the rectum
   • The average distance from the anal verge to the prostate apex is approximately 4.86 cm 3

3. Systematic Assessment:

   • Assess the prostate for:
     • Size and symmetry
     • Consistency (normally feels like the thenar eminence of the hand)
     • Presence of nodules, induration, or asymmetry
     • Tenderness
   • Examine the posterior, lateral, and accessible portions of the prostate gland

Anatomical Considerations and Limitations

• It's important to recognize that complete palpation of the prostate is often not possible during DRE:

  • Only 3.2% of prostates can be palpated in their entirety 4
  • 93.7% of the apex, 66.3% of half the prostate, and 23.2% of three-quarters of the prostate can typically be palpated 4
  • The base of the prostate is often beyond reach of the examining finger

• Factors limiting complete examination:

  • Anatomical location of the prostate
  • Prostate volume
  • Length of examiner's index finger (average is 7.3 cm) 3
  • Patient's body habitus (BMI significantly affects palpability) 2

Improving Examination Adequacy

• If the prostate is incompletely felt on initial examination, have the patient flex his knee(s) up toward his chest
  • This simple maneuver improves complete palpation in 95% of initially difficult cases 2
• In obese patients (BMI >30), be aware that prostate palpation is more challenging, with 61.8% having incomplete palpation on initial examination 2

Clinical Significance and Interpretation

• A "high-riding" prostate is defined as the apex being more than 6.2 cm from the anal verge 3
• Normal prostate feels smooth, rubbery, and symmetric
• Suspicious findings warranting further evaluation:
  • Nodules
  • Asymmetry
  • Areas of induration
  • Irregularity in contour

While DRE is recommended as part of prostate cancer screening in conjunction with PSA testing 5, it's important to recognize its limitations. Recent evidence suggests that DRE has limited diagnostic value as a standalone screening test for prostate cancer, with a cancer detection rate significantly lower than PSA testing (1% vs. 3%) 6.